The Myers-Briggs Type Indicator is a simple set of four pairs of preferences that you can use to give some idea of your character's personality type. This is not a restriction on how you roleplay your character, it is simple a hint to the GMs as to how your character's mind works (and a tool we can use to help make decisions if needed when resolving turnsheet actions).

Note that we're not using the proper Myers-Briggs Type Indicator; this is a slightly simplified version tuned more for the GMs benefit.

Does your character prefer to think through a problem rationally and examine it carefully from the outside before coming to a decision, or do they prefer to get inside a problem and make a decision based on what feels right?